PolyPro and PVC/CPVC PVC pipes are commonly used for venting water heaters, condensing boilers and warm air furnaces, but PVC and CPVC was never designed for such use. PVC has as max temperature of 149 Degrees F and CPVC is 194 Degrees F, which is often lower than what a Condensing Boiler would kick out if not in Condensing mode. Also, PVC will become illegal for venting in the USA at some point, as it is now in Canada and most of Europe.

Duravent PolyPro 3PPS-FK Chimney Lining Kit is designed to allow a max temperature of 230 Degrees F and should be used on some of the Condensing Boilers and Condensing Tankless Water Heaters that we sell. Zero Clearance to combustables for up to 190 Degrees for both Vertical and Horizontal instllations. Up to 230 Degrees is Zero Clearance for Vertical installs and 1/4 inch clearance for horizontal instllations.